The present invention relates to an extensometer that measures a change in distance. More particularly, the present invention relates to an extensometer having an improved flexure assembly.
Extensometers are commonly used for measuring strain in a test specimen. Numerous forms of extensometers have been advanced in the art. One common form includes an extensometer having a pair of arms with first ends of the arms contacting surfaces of the specimen to be tested. At ends opposite the test specimen, the arms are mounted together with a flexure assembly comprising a first flexure plate or member and a second flexure plate or member. The flexure plates are joined together to form a hinge assembly with each flexure plate substantially perpendicular to the other. With elongation or compression of the test specimen, the arms move in an arc since the arms are hinged at the flexure assembly.
Although the above-described extensometer is well suited for many applications, the extensometer is not easily adaptable to be used with displacement sensors such as an LVDT (linear variable differential transformer) sensor. As is known, the LVDT sensor typically comprises an inner rod assembly that moves longitudinally through an aperture of an outer housing. Since the arms of the above-described extensometer travel in an arc, the LVDT sensor cannot be mounted to the extensometer because the inner rod assembly will contact a perimeter wall of the aperture or components located in the outer housing.